480 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



arisen from a reckless use of the material. The endeavors of 

 Mr. Noble to diminish the chances of the accidental explo- 

 sion of the liquid substance led to the production by him, in 

 1867, of the solid preparation of nitro-glycerine, known un- 

 der the name of dynamite, which constitutes, as now manu- 

 factured, one of the safest, most powerful, and most con- 

 venient explosive agents. Dynamite, as originally prepared, 

 consisted of about 75 per cent, of nitro-glycerine absorbed 

 by about 25 per cent, of a porous, infusorial, silicious earth 

 found in Germany. This substance is now furnished to the 

 trade in cartridges whose charges have the consistency of dry 

 putty. During the late siege of Paris attempts were made 

 in that city to substitute some other earth for that used in 

 Germany. The most efficient absorbents were found to be 

 silica, tripoli, alumina, and sugar. None of these, however, 

 is considered to be so efficient as the German mineral. The 

 preparation called glypto-fractur is stated to be a secret com- 

 position, but it has been publicly acknowledged by the man- 

 ufacturers that the material is a modified dynamite, for 

 w 7 hich, however, special merits in regard to safety and pow- 

 er are claimed. It is difficult, however, to conceive that it 

 can be more powerful than the original pure dynamite, from 

 which it differs principally in containing a larger percent- 

 age of earths. Professor Abel believes that Noble's dynamite 

 has a decided superiority over glypto-fractur in respect to 

 the retention of nitro-glycerine at different temperatures. 

 Exploding nitro-glycerine in its pure or liquid form is pre- 

 eminently dangerous, and therefore only likely to receive 

 exceptional application. 



Professor Abel makes a comparison between the destruc- 

 tive effects of dynamite and compressed gun-cotton, and states 

 that, generally, in all operations where rapid destruction is 

 to be accomplished, gunpowder is undoubtedly inferior to 

 these new explosive agents. Not only would a much larger 

 quantity of powder be required to produce similar results, 

 but in some cases it would be impossible to perform the 

 same operations. In tunneling in the slate quarries of North 

 Wales, a work that costs 60 shillings per cubic yard for 

 gunpowder is done in less time for 45 shillings per yard 

 with compressed gun-cotton. In experiments made by Mr. 

 llawkshaw, it was found that a detonation of gun-cotton 



